1. Field of the Invention
The present invention relates to a container with double layers made of different materials, more particularly one, which is made in such a way that both of the layers can""t separate from each other, move relatively to each other or change shape due to significant change of temperature or hit of other objects.
2. Brief Description of the Prior Art
Containers usually have patterns printed or attached on the surface to be attractive. However, patterns on the surface of a container are likely to be damaged or fade if hard objects are rubbed against them or if they are subject to moisture, or after the container has been used for a long period of time.
Referring to FIG. 5, a conventional container 10 is comprised of outer and inner layers 11, and 12; the outer layer 11 is formed with ornamental through holes 111 with various shapes on the annular portion; the inner layer 12 is disposed in the outer layer 11 so that patterns can be presented by means of the ornamental through holes 111 and the inner layer 12; the inner layer 12 can be merely closely fitted to the outer layer 11 without use of adhesive or securely joined to the outer layer 11 with adhesive. This container 10 is found to have disadvantages as followings:
1. Adhesive used between the layers 11, 12 is likely to become loose, causing the layers 11, 12 to easily separate from each other if the layers are made of different materials to have different coefficients of expansion, and there is significant change of temperature.
2. The layers 11, 12 are prone to move relatively with respect to each other, and even change shape if the inner layer 12 is merely closely fitted into the outer layer 11 without use of adhesive, and other objects hit the container hard.
3. The through holes 111 of the outer layer 11 make the container uneven on the surface. Consequently, the appearance of the container is badly affected.
Referring to FIG. 6, another conventional container 20 is comprised of outer and inner layers 21, and 22 made of different materials; the outer layer 21 is formed with an injection gate 212 on the bottom, and ornamental through holes 211 with various shapes on the annular portion; the inner layer 22 is made, and the holes 211 are filled with plastic materials for the outer layer 22 by means of positioning the outer layer 21 on a mold, and injecting the plastic materials into the mold via the gate 212; thus, both the layers 21, 22 are joined together, and plastics formed in the holes 211 are as high as those portions of the outer layer 21 that surround the through holes 211, i.e. the container 20 is smooth on the surface thereof. However, this container 20 still has disadvantages as followings:
1. Because the layers 11, 12 are made of different materials to have different coefficients of expansion, they are prone to separate from each other when there is significant change of temperature.
2. The layers 21, 22 are prone to move relative to each other, and even change shape when other objects hit the container hard.
3. The injection gate 212 on the bottom of the outer layer 21 will make the whole container take on an unpleasant appearance.
4. The patterns are flat, which are presented by the plastics formed in the through holes 211 in the injection molding for the inner layer 22.
It is a main object of the present invention to provide a container with double layers made of different materials, of which both of the layers can""t easily separate from each other, move relatively to each other or change shape.
The container of the invention includes a metallic outer layer formed with through holes, and a plastic inner layer formed directly over an inner side of the outer layer by means of injection molding with a mold; the mold is shaped such that three-dimensional projecting portions are formed over corresponding ones of the through holes of the outer layer and project beyond the outer layer in the injection molding, and that edges of the projecting portions mount on those portions of the outer layer that define the through holes.